%0 Journal Article
%T Limitations to photosynthesis at different temperatures in the leaves of Citrus limon
%A Pimentel
%A Carlos
%A Bernacchi
%A Carl
%A Long
%A Steve
%J Brazilian Journal of Plant Physiology
%D 2007
%I Scientific Electronic Library Online
%R 10.1590/S1677-04202007000200006
%X the response of co2 assimilation rate (a) to the intercellular partial pressure of co2 (ci) was measured on intact lemon leaves over a range of temperatures (10 to 40oc). the a/ci response shows how change in the leaf temperature alters the activity of ribulose-1,5-bisphosphate (rubp) carboxylase-oxygenase (rubisco) and rubp regeneration via electron transport. the rate of a reached a maximum of 7.9 to 8.9 ¦̀mol m-2 s-1 between 25 and 30oc, while dark respiration (rd) increased with temperature from 0.4 ¦̀mol m-2 s-1 at 10oc to 1.4 ¦̀mol m-2 s-1 at 40oc. the maximum rates of carboxylation (vc,max) and the maximum rates of electron transport (jmax) both increased over this temperature range from 7.5 to 142 ¦̀mol m-2 s-1 and from 23.5 to 152 ¦̀mol m-2 s-1, respectively. these temperature responses showed that a can be limited by either process depending on the leaf temperature, when ci or stomatal conductance are not limiting. the decrease in a associated with higher temperatures is in part a response to the greater increase in the rate of oxygenation of rubp compared with carboxylation and rd at higher temperatures. although a can in theory be limited at higher ci by the rate of triose-phosphate utilization, this limitation was not evident in lemon leaves.
%K a/ci curves
%K gas exchange
%K lemon.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1677-04202007000200006&lng=en&nrm=iso&tlng=en